Detection device

ABSTRACT

A magnetic detection module is provided so as to be selectively mountable in any of housings having a plurality of specifications having different shapes or sizes of mounting portions, and detects magnetic flux generated in the housing. The magnetic detection module includes one or more magnetic sensors that detect magnetic flux, a case in which the magnetic sensors are housed, and a cap that can be attached to an end of the case and is provided with a sealing member. The magnetic detection module can be attached to the housing of the first specification with the cap not attached to the case, and can be attached to the housing of the second specification through a sealing member with the cap attached to the case.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. Utility application Ser. No.17/129,094 filed on Dec. 21, 2020, which is a continuation applicationof International Patent Application No. PCT/JP2019/024190 filed on Jun.19, 2019, which is based on and claims the benefits of priorities ofJapanese Patent Application No. 2018-123160 filed on Jun. 28, 2018, andJapanese Patent Application No. 2018-195711 filed on Oct. 17, 2018. Theentire disclosure of all of the above applications is incorporatedherein by reference.

TECHNICAL FIELD

The present disclosure relates to a magnetic detection module, adetection device, a case assembly, and a production method for themagnetic detection module.

BACKGROUND

Conventionally, a detection device that detects a magnetic fluxgenerated in response to a movement of a movable body is known.

SUMMARY

[Purpose of Disclosure of First Group]

A purpose of the disclosure of the first group is to provide a magneticdetection module that can be selectively attached to a plurality ofhousings having different specifications by a simple configurationchange using a common component, a case assembly constituting themagnetic detection module, and its production method.

[Purpose of Disclosure of Second Group]

The purpose of the disclosure of the second group is to provide adetection device for preventing interference between a sensor unitprotruding from the tip surface and a member on the housing side and amagnetic detection module, in the detection device in which a magneticdetection module is mounted on a housing having a mounting hole whoseinner wall has a cylindrical shape.

[Disclosure of First Group]

The magnetic detection module of the present disclosure is provided soas to be selectively mountable in any of housings having a plurality ofspecifications having different shapes or sizes of mounting portions,and detects magnetic flux generated in the housing. The magneticdetection module includes one or more magnetic sensors that detectmagnetic flux, a case in which the magnetic sensors are housed, and acap that can be attached to an end of the case and is provided with asealing member.

[Disclosure of Second Group]

The detection device of the present disclosure includes a housing and amagnetic detection module. The housing has a mounting hole providedinside with a set of yokes that transmit the magnetic flux generatedaccording to a magnitude of a physical quantity to be detected. Themagnetic detection module is mounted in a mounting hole in the housingand detects the magnetic flux transmitted from the yoke by one or moremagnetic sensors housed in a case. A set of yokes face each other andhave rings that form a magnetic circuit.

BRIEF DESCRIPTION OF DRAWINGS

The above and other objects, features and advantages of the presentdisclosure will become more apparent from the following detaileddescription made with reference to the accompanying drawings. In thedrawings:

FIG. 1 is an exploded perspective view illustrating a basicconfiguration of a torque detection device to which a magnetic detectionmodule is applied;

FIG. 2A is a front view of a magnetic detection module mounting portionof a housing in a column-mounted type (non-waterproof specification);

FIG. 2B is a perspective view of FIG. 2A;

FIG. 3A is a front view of the magnetic detection module mountingportion of a housing in a rack-mounted type (waterproof specification);

FIG. 3B is a perspective view of FIG. 3A;

FIG. 4 is an exploded perspective view of the magnetic detection moduleaccording to a first embodiment;

FIG. 5A is a cross-sectional view of a cap and a case assembly;

FIG. 5B is a cross-sectional view of a torque detection device which thecase assembly is independently mounted in a non-waterproof housing;

FIG. 6A is a side view of the magnetic detection module with the capattached to the case assembly;

FIG. 6B is a cross-sectional view of a torque detection device in whicha case assembly with cap attached is attached to a waterproof housing;

FIG. 7A is a plan view of the case assembly alone;

FIG. 7B shows a front surface as seen by an arrow VIIB of FIG. 7A;

FIG. 8A is a plan view of the case assembly with the cap attached;

FIG. 8B shows a front surface as seen by an arrow VIIIB of FIG. 8A;

FIG. 9A is a schematic cross-sectional view of a torque detection devicein which a cap is attached to a housing according to a firstmodification of the first embodiment;

FIG. 9B is a cross-sectional view taken along line IXB-IXB of FIG. 9A;

FIG. 10 is a perspective view of a mounting hole of the housing to whichthe cap of FIG. 9A is attached;

FIG. 11A is a schematic cross-sectional view of a torque detectiondevice in which a cap according to a second modification of the firstembodiment is attached to a housing;

FIG. 11B is a cross-sectional view taken along line XIB-XIB of FIG. 11A;

FIG. 12 is a perspective view of a mounting hole of the housing to whichthe cap of FIG. 11A is attached;

FIG. 13A is a plan view illustrating a magnetic transmission actionbetween a yoke and a magnetic flux guiding member when the magneticdetection module is attached to the housing;

FIG. 13B is a side view as seen by arrow XIIIB of FIG. 13A;

FIG. 14 is an axial sectional view taken along line XIV-XIV of FIG. 13A;

FIG. 15 is a correlation diagram between a distance from a referenceline and a magnetic permeance;

FIG. 16 is a flowchart of a production method for a magnetic detectionmodule;

FIG. 17A is a plan view of the case assembly unit of a second embodimentin which the case is provided with the magnetic shield member;

FIG. 17B shows a cross-sectional view taken along line XVIIB-XVIIB ofFIG. 17A of the magnetic shield member and the case assembly;

FIG. 17C shows a cross-sectional view of the case assembly provided withthe magnetic shield member;

FIG. 18A is a plan view of the magnetic detection module of the secondembodiment in which the cap is provided with the magnetic shield member;

FIG. 18B is a cross-sectional view taken along the line XVIIIB-XVIIIB ofFIG. 18A;

FIG. 19 is a cross-sectional view of a torque detection device in whicha magnetic detection module according to a third embodiment is attachedto a housing;

FIG. 20 is a cross-sectional view of a torque detection device in whicha magnetic detection module according to a fourth embodiment is attachedto a housing;

FIG. 21 is a schematic cross-sectional view (1) showing a dimensionalrelationship of the third and fourth embodiments;

FIG. 22 is a schematic cross-sectional view (2) showing a dimensionalrelationship of the third and fourth embodiments;

FIG. 23A is a cross-sectional view of a cylindrical portion in the A-Aline cross section of FIGS. 21 and 22 showing the shape example 1 of arotation regulation (prevention of erroneous assembly) portion;

FIG. 23B is a front view of a housing mounting hole according to anarrow in a B direction of FIGS. 21 and 22 , which shows a shape example1 of a rotation regulation (prevention of erroneous assembly) portion;

FIG. 24A shows a shape example 2 of the rotation regulation (preventionof erroneous assembly) portion, and is a diagram conforming to FIG. 23A;

FIG. 24B shows a shape example 2 of the rotation regulation (preventionof erroneous assembly) portion, and is a diagram conforming to FIG. 23B;

FIG. 25A shows a shape example 3 of the rotation regulation (preventionof erroneous assembly) portion, and is a diagram conforming to FIG. 23A;

FIG. 25B shows a shape example 3 of the rotation regulation (preventionof erroneous assembly) portion, and is a diagram conforming to FIG. 23B;

FIG. 26A is a cross-sectional view of a cap and case assembly using capof other embodiments;

FIG. 26B is a side view of the magnetic detection module with the cap ofother embodiment mounted on the case assembly; and

FIG. 27 is a schematic configuration diagram of an electric powersteering device to which the torque detection device is applied.

DETAILED DESCRIPTION

In an assumable example, a detection device that detects a magnetic fluxgenerated in response to a movement of a movable body is known. In apower steering device of a vehicle, for example, a torque sensor uses amagnetic sensor to detect changes in magnetic flux generated by atorsional displacement of a torsion bar housed in a housing, and detectsa steering torque. This torque sensor has a cylinder portion having aspigot structure that is joined to a mounting hole of a housing in asensor holder. A seal member is compressed and interposed between themounting hole of the housing and an outer peripheral surface of thecylinder portion with the spigot structure to seal between the two.Then, an elastic force of the seal member acts on the cylinder portionwith the spigot structure in a radial direction of the outer peripheralsurface of the cylinder portion.

Further, a detection device has a configuration in which a magneticdetection module including a magnetic sensor is inserted into a mountinghole of a housing. For example, in a torque detection device, a case(that is, a magnetic detection module) including a detection unit, adetection circuit board, and the like is inserted into a through hole(that is, a mounting hole) from a radial direction of the housing. Anouter end of the through hole in the housing and an outer surface of thecase have positioning surfaces that determine the position of thedetection unit in the housing.

[First Viewpoint]

Generally, as a structure of a detection device that detects magneticflux generated in response to movement of a movable body, a magneticdetection module having a magnetic sensor and outputting a detectionsignal to the outside is attached to a housing in which a movable bodyand a magnetic flux generating portion are housed. The magneticdetection module includes a case assembly in which the magnetic sensoris housed in the case. The case assembly includes a substrate on which asignal output circuit is mounted, a connector to which a signal line iswired, and the like in addition to the magnetic sensor. With such amodule structure, in an actual product, the magnetic detection modulesupplied as a component from another place is attached to the housing atan assembly factory.

By the way, the torque sensor disclosed in Patent Document 1 includes aseal member, but in reality, depending on the part of the vehicle onwhich the torque sensor is mounted, the rack-mounted type is required tohave a waterproof function, and the column-mounted type is not requiredto have a waterproof function. Therefore, when applied to a waterproofdetection device, it is necessary to provide a sealing member betweenthe magnetic detection module and the housing. When applied tonon-waterproof detection device, it is not necessary to provide asealing member between the magnetic detection module and the housing.

If a case dedicated to each of the waterproof and non-waterproofhousings is manufactured by, for example, resin molding, two types ofmolds are required, and production adjustment and inventory managementman-hours for the two types of cases are required. Further, for example,when there are a plurality of specifications having different shapes andsizes of sealing members among the waterproof specifications, it isnecessary to switch the production of other models, and the mold costand the management cost are increased.

[Second Viewpoint]

In the configuration of Patent Document 2, an inner wall of the mountinghole of the housing has a rectangular tubular shape. On the other hand,Patent Document 2 does not specifically specify the positioningconfiguration when the inner wall of the mounting hole of the housinghas a cylindrical shape.

Further, in the configuration of Patent Document 2, since an outerperipheral of the insertion portion is surrounded by a magnetic ring,there is no risk that the housing portion of the magnetic sensor willcome into direct contact with the housing during the insertion work andbe damaged. On the other hand, in a configuration in which the sensorunit in which the magnetic sensor is housed protrudes from a tip surfaceof the magnetic detection module, if the sensor unit interferes with amember on the housing side due to misalignment or tilt during insertion,the magnetic sensor may be damaged or its characteristics may change.

[Purpose of Disclosure of First Group]

A purpose of the disclosure of the first group is to provide a magneticdetection module that can be selectively attached to a plurality ofhousings having different specifications by a simple configurationchange using a common component, a case assembly constituting themagnetic detection module, and its production method.

[Purpose of Disclosure of Second Group]

The purpose of the disclosure of the second group is to provide adetection device for preventing interference between a sensor unitprotruding from the tip surface and a member on the housing side and amagnetic detection module, in the detection device in which a magneticdetection module is mounted on a housing having a mounting hole whoseinner wall has a cylindrical shape.

[Disclosure of First Group]

The magnetic detection module of the present disclosure is provided soas to be selectively mountable in any of housings having a plurality ofspecifications having different shapes or sizes of mounting portions,and detects magnetic flux generated in the housing. The magneticdetection module includes one or more magnetic sensors that detectmagnetic flux, a case in which the magnetic sensors are housed, and acap that can be attached to an end of the case and is provided with asealing member.

This magnetic detection module can be attached to the housing of thefirst specification with the cap not attached to the case, and can beattached to the housing of the second specification through the sealingmember with the cap attached to the case. The sealing member is notprovided at the time when the cap is attached to the case, and may beprovided before the cap is attached to the housing.

For example, this magnetic detection module further includes one or moremagnetic flux guiding members in the case that guide the detectedmagnetic flux to the magnetic sensor.

In the present disclosure, the mounting specifications for the housingcan be changed depending on the presence or absence of the cap.Specifically, for the waterproof housing, a magnetic detection module inwhich a cap provided with a sealing member is attached to the case issupplied. Further, for the non-waterproof housing, the case assemblywithout the cap is independently supplied as a magnetic detectionmodule. Therefore, for example, when the case is manufactured by resinmolding, only one type of mold is required for the case, and inventorymanagement is simplified.

In addition, a case assembly that constitutes the above magneticdetection module is provided. The case assembly includes one or moremagnetic sensors that detect magnetic flux and a case that houses themagnetic sensor. This case assembly can be independently attached to thehousing of the first specification, and can be attached to the housingof the second specification through the sealing member with the capprovided with the sealing member attached to the end of the case.

Further, a production method for the above-mentioned magnetic detectionmodule is provided. The production method of this magnetic detectionmodule includes a storage process, a selection process, and a mountingprocess. In the storage process, one or more magnetic sensors thatdetect magnetic flux are housed in a case, and a case assembly ismanufactured. In the selection process, according to the specificationsof the housing to be attached, it is selected whether to use the caseassembly alone or to attach a cap set for each housing specification tothe end of the case. In the mounting process, when it is selected tomount the cap on the case in the selection step, the cap is mounted andfixed to the case.

[Disclosure of Second Group]

The detection device of the present disclosure includes a housing and amagnetic detection module. The housing has a mounting hole providedinside with a set of yokes that transmit the magnetic flux generatedaccording to a magnitude of a physical quantity to be detected. Themagnetic detection module is mounted in a mounting hole in the housingand detects the magnetic flux transmitted from the yoke by one or moremagnetic sensors housed in a case. A set of yokes face each other andhave rings that form a magnetic circuit.

The mounting hole of the housing has a large hole formed on an openingside and a small hole formed in a back of the large hole. The magneticdetection module has a cylinder portion and a sensor unit. The cylinderportion has a large shaft portion that faces the inner wall of themounting hole and is inserted into the large hole, and a small shaftportion that is inserted into the small hole. The cylinder portion maybe integrally formed with the case. Alternatively, the cylinder portionmay be composed of a plate-shaped cap body of a cap attached to an endportion of the case. The sensor unit accommodates the magnetic sensor,projects from the tip surface of the cylinder portion, and is insertedbetween the ring portions of the set of yokes.

A minimum distance between the sensor unit and the ring portion in adirection orthogonal to the axial direction of the mounting hole and thecylinder portion is defined as “sensor margin”. At least one of theone-sided fitting gap between the large hole and the large shaft portionor the one-sided fitting gap between the small hole and the small shaftportion is set to be smaller than the sensor margin.

For example, the “cylindrical portion” is formed as a cylindrical“cylindrical portion”. In this case, “large hole”, “small hole”, “largeshaft part” and “small shaft part” are read as “large diameter hole”,“small diameter hole”, “large diameter part” and “small diameter part”,respectively. Further, the “direction orthogonal to the axial directionof the cylindrical portion” is read as “radial direction of thecylindrical portion”.

As a result, the detection device of the present disclosure suppressesmisalignment and inclination when the magnetic detection module isinserted into the mounting hole. Therefore, it is prevented that thesensor unit interferes with the ring portion of the yoke, which is amember on the housing side. In addition, a magnetic detection moduleattached to a housing in the above detection device is provided.

Hereinafter, a plurality of embodiments of a detection device and amagnetic detection module will be described with reference to thedrawings. In the following embodiments, substantially same structuralparts are designated with the same reference numerals thereby tosimplify the description. The detection device of the present embodimentfunctions as a torque detection device that detects steering torque inan electric power steering device. Further, the magnetic detectionmodule of the present embodiment is applied to the torque detectiondevice. The first and second embodiments correspond to “disclosure of afirst group”. The third and fourth embodiments also correspond to“disclosure of a second group”. In particular, a configuration in whichan O-ring, which is a sealing member, is attached in the thirdembodiment also corresponds to “disclosure of the first group”.

First, with reference to FIG. 1 , a basic configuration of the torquedetection device 10 as “detection device” will be described. The torquedetection device 10 includes a magnetic detection module 90 and detectstorque based on magnetic flux generated according to the input torque.

The torque detection device 10 includes an element housed in a housing40 mounted on a vehicle and an element configured as a magneticdetection module 90 and attached to the housing 40. The element housedin the housing 40 includes a torsion bar 13, a multipolar magnet 14, aset of yokes 31, 32, and the like. The element configured as themagnetic detection module 90 include magnetic flux guiding members 601,602, magnetic sensors 71, 72 and the like.

One end portion of the torsion bar 13 is fixed to an input shaft 11 witha pin 15, and another end portion of the torsion bar 13 is fixed to anoutput shaft 12 with a pin 15 so that the input shaft 11 and the outputshaft 12 are connected on a same axis as a central axis O. The torsionbar 13 is an elastic member having a rod shape for converting a steeringtorque applied to a steering shaft 94 to a torsional displacement. Inthe multipolar magnet 14, which is secured to the input shaft 11, theN-poles and S-poles are disposed alternately in a circumferentialdirection.

The set of yokes 31 and 32 is made of a soft magnetic material and isfixed to the output shaft 12 on an outer diameter of the multipolarmagnet 14. Each yoke 31, 32 has a ring portion 35, 36 facing each othervia a gap in an axial direction, and a plurality of claws 33, 34extending axially from an inner peripheral edge of each ring portion 35,36 toward the other ring portion. The same number of claws 33 and 34 asthe north and south poles of the multipolar magnet 14 are provided atequal intervals on the entire circumference along the inner peripheraledge of the ring portions 35 and 36. The claws 33 of the yoke 31 and theclaws 34 of the yoke 32 are shifted in the circumferential direction,placed alternately. The pair of yokes 31 and 32 thus forms a magneticcircuit in a magnetic field generated by the multipolar magnet 14.

The central axis O may be defined using any of the torsion bar 13, themultipolar magnet 14, and the yokes 31 and 32 as the reference, sincethey are all placed concentrically. In the present specification, it isbasically described as “the central axis O of the yokes 31 and 32” withreference to the yokes 31 and 32 in which the facing relationship withthe magnetic flux guiding members 601 and 602 is focused. In thedescription of the embodiments, an axial direction and a radialdirection of the torsion bar 13, the multipolar magnet 14, the yokes 31and 32, and the like are simply referred to as the “axial direction” andthe “radial direction.”

The magnetic flux guiding members 601 and 602 of the magnetic detectionmodule 90 are made from a soft magnetic member, and a set of yokes 31and 32 and a main body 600 face each other in the axial direction toguide the magnetic flux of the magnetic circuit to the magnetic sensors71 and 72. In the present embodiment, a set of magnetic flux guidingmembers 601 and 602 facing each other in the axial direction areprovided.

Hereinafter, for convenience of explanation, the yoke 31 and themagnetic flux guiding member 601 arranged on the first shaft 11 side inFIG. 1 are referred to as “upper yoke 31” and “upper magnetic fluxguiding member 601”. Further, the yoke 32 and the magnetic flux guidingmember 602 arranged on the second shaft 12 side are referred to as“lower yoke 32” and “lower magnetic flux guiding member 602”. The uppermagnetic flux guiding member 601 faces the upper yoke 31, and the lowermagnetic flux guiding member 602 faces the lower yoke 32.

The set of magnetic flux guiding members 601 and 602 of the presentembodiment has two extensions 61 and 62 branched from the main body 600.Specifically, the extensions 61 and 62 extend from the main body 600toward the outside of the yokes 31 and 32 in the radial direction. Themagnetic sensor 71 is disposed between the extensions 61, and themagnetic sensor 72 is disposed between the extensions 62. The extensions61 each have a step in the axial direction so as to have a minimum gaptherebetween in a location where the magnetic sensor 71 is placed. Theextensions 62 each have a step in the axial direction so as to have aminimum gap therebetween in a location where the magnetic sensor 72 isplaced.

The magnetic sensors 71 and 72 detect the magnetic flux induced by themagnetic flux guiding members 601 and 602 from the ring portions 35 and36 of the set of yokes 31 and 32, convert it into a voltage signal, andoutput an external processing unit via a harness. Each of the magneticsensors 71 and 72 is, for example, an IC package having a substantiallyrectangular parallelepiped shape, made using a Hall element,magneto-resistive element, or the like molded in resin. The magneticdetection module 90 of the present embodiment includes two magneticsensors 71 and 72, and redundantly outputs two values as steering torqueto the processing unit. With such a redundant configuration, theprocessing unit can continue to control even if one of the informationbecomes unusable due to a failure of the magnetic sensor or thearithmetic circuit.

Here, with reference to FIG. 27 , a schematic configuration of anelectric power steering device to which the torque detection device isapplied will be described. While the electric power steering system 100illustrated in FIG. 27 is of a column assist type, the torque detectiondevice can be also used in rack assist electric power steering systems.

The torque detection device 10 for detecting steering torque isinstalled on a steering shaft 94 connected to a steering wheel 93. Apinion gear 96 is provided at a tip of the steering shaft 94, and apinion gear 96 meshes with a rack shaft 97. A pair of wheels 98 arerotatably connected to both ends of the rack shaft 97 via a tie rod orthe like. A rotational movement of the steering shaft 94 is convertedinto linear movement of the rack shaft 97 by the pinion gear 96, and thepair of road wheels 98 is steered.

The torque detection device 10 is provided between the input shaft 11and the output shaft 12 constituting the steering shaft 94, detects thesteering torque applied to the steering shaft 94, and outputs the torqueto an ECU 91. The ECU 91 controls an output of a motor 92 in accordancewith the detected steering torque. The motor 92 generates a steeringassist torque that is reduced by a reduction gear 95 and transmitted tothe steering shaft 94.

Next, a structure for attaching the magnetic detection module 90 to thehousing 40 will be described. In the present embodiment, it is assumedthat the housing 40 has two specifications in which the shape or size ofthe mounting portion is different. The housing 401 shown in FIGS. 2A and2B is a column-mounted type housing provided on the steering shaft ofthe electric power steering device. The housing 402 shown in FIGS. 3Aand 3B is a rack-mounted type housing provided on the rack shaftconnecting the pinion gear at the tip of the steering shaft and thewheel.

The rack-mounted type housing 402 is in an environment where rainwateror the like is splashed from the road surface when the vehicle istraveling or the like. Therefore, in order to prevent water fromentering the inside of the housing through the gap of the mountingportion, it is necessary to provide a sealing member on the mountingportion. On the other hand, in the column-mounted type housing 401provided in the vehicle interior, there is no risk of water entering, soit is not necessary to provide a sealing member on the mounting portion.

That is, there are the non-waterproof housing 401 and the waterproofhousing 402 depending on the mounting portion of the torque detectiondevice 10 in the vehicle. The housing 401 corresponds to the “housing ofthe first specification”, and the housing 402 corresponds to the“housing of the second specification”. In addition, in thisspecification, “water” in “waterproof” means not only pure water but allliquids which may infiltrate the housing.

Both the housings 401 and 402 have a substantially cylindrical shapewith the axis O as the central axis, and have a flat mounting plate 400formed on a part of the outer periphery thereof. In the description ofthe housings 401 and 402, the upper side in FIGS. 2A and 3A is referredto as “upper” and the lower side is referred to as “lower” forconvenience. The mounting plate 400 has mounting holes 41 and 42 formedacross a plane including the central axis O, and fixing holes 48 such asbolts are formed on both sides of the mounting holes 41 and 42 in thecircumferential direction. The alternate long and short dash lineindicates a portion where a flange 57 shown in FIGS. 7B and 8B abuts,and a fixing hole 48 corresponds to a position of a fixing hole 58 ofthe flange 57.

As shown in FIGS. 2A and 2B, in the column-mounted type housing 401, themounting holes 41 are formed in a substantially rectangular shape. Onerotation restricting groove 44 is formed in a lower center of themounting hole 41, and two rotation restricting grooves 45 are formed inthe upper portions of both sides of the mounting hole 41. The rotationrestricting groove 44 at the lower center is formed relativelyshallowly, and the rotation restricting grooves 45 at the upper portionson both sides are formed relatively deeply. The functions of therotation restricting grooves 44 and 45 will be described later withreference to FIG. 5B.

As shown in FIGS. 3A and 3B, in the rack-mounted type housing 402, themounting hole 42 includes a substantially rectangular case hole 421 on aback side in a depth direction and a circular seal hole 422 in a middlein the depth direction, and a circular spigot hole 423 on an end faceside. Further, in the upper center of the spigot hole 423, one rotationrestricting groove 471 is formed continuously with the spigot hole 423.The function of the rotation restricting groove 471 will be describedlater with reference to FIG. 6B.

It is also possible to manufacture a case dedicated to each of thespecifications of the magnetic detection module 90 for the two types ofhousings 401 and 402 having different shapes and sizes of the mountingportions. However, in that case, two types of resin molding dies arerequired, and production adjustment and inventory management man-hoursfor two types of cases are required. Therefore, in the first and secondembodiments, it is an object to provide the magnetic detection modulethat can be selectively mounted on two types of housings 401 and 402having different specifications by a simple configuration change usingcommon components.

First Embodiment

Subsequently, a specific configuration of the magnetic detection moduleof the first embodiment will be described. The first embodiment reflectsa basic technical idea regarding case sharing. The second embodimentfurther includes a magnetic shield member that blocks magnetic noisefrom the outside as compared with the first embodiment. Hereinafter,with respect to the reference numerals of the detection device and themagnetic detection module of each embodiment, the number of theembodiment is assigned to the third digit following “10” and “90”.Regarding the reference numerals of the constituent members, in the caseof a configuration peculiar to the embodiment, the number of theembodiment is similarly assigned to the third digit, and in the case ofsubstantially the same configuration as the above-described embodiment,the reference numerals of the above-described embodiment are used.

The configurations of the torque detection device 101 and the magneticdetection module 901 of the first embodiment will be described withreference to FIGS. 4 to 8B. The magnetic detection module 901 includes acase assembly 500 and a cap 801. The case assembly 500 includes a case501, magnetic flux guiding members 601, 602, magnetic sensors 71, 72, asubstrate 70, and the like housed in a box portion 51 of the case 501.The magnetic flux guiding members 601 and 602 and the magnetic sensors71 and 72 are as described above, as shown in FIG. 1 . In addition tothe magnetic sensors 71 and 72, a sensor signal output circuit and thelike are mounted on the substrate 70.

The case 501 is formed of a resin and has a rectangular parallelepipedbox portion 51, a connector portion 56 to which a harness fortransmitting a signal to an external processing unit is connected,flanges 57 formed with fixing holes 58 for mounting on the housings 401and 402, and the like. A terminal 73 connected to the substrate 70 isinsert-molded between a bottom of the box portion 51 and a bottom of theconnector portion 56. The substantially rectangular substrate 70 onwhich the magnetic sensors 71 and 72 are mounted is installed on thebottom of the box portion 51.

Hereinafter, for convenience of explanation, an opening end 52 side ofthe box portion 51 is regarded as upper side, and the bottom side of thebox portion 51 is regarded as lower side. Further, the side on which themagnetic sensors 71 and 72 of the box portion 51 is mounted is regardedas front side, and the connector portion 56 side is regarded as rearside. An end portion of the case 501 located on the front side withrespect to the flange 57 of the box portion 51 forms an insertionportion 53. In the column of “Brief description of the drawing”, theview seen from the opening end 52 side is represented as a plan view,and the view viewed from the insertion portion 53 side is represented asa front view. In the following description, “in plan view” is used tomean “when viewed from the opening end 52 side”.

As shown in FIGS. 7A, 7B, etc., the insertion portion 53 has arectangular parallelepiped shape including a front wall 531, side walls532, and a bottom wall 533. On the edges of the side walls 532 on bothsides on the opening end 52 side, protrusion portions 55 are formed as“misassembling prevention portion” and “rotation regulation portion”that project on the upper side. Further, on the lower surface of the boxportion 51, a protrusion portion 54 as a “misassembling preventionportion” and a “rotation regulating portion” projecting on the lowerside is provided at the central portion in the left-right direction andnear the flange 57 in the front-rear direction.

When the case 501 or the cap 801 is assembled to the housing 40, the“misassembling prevention portion” can be assembled only in a posturelocated at a predetermined relative angle, and prevents erroneousassembly in a posture located at a position other than the predeterminedrelative angle. The “rotation regulation portion” regulates rotationwith respect to the housing 40 after the case 501 or cap 801 isassembled to the housing 40.

Each of the set of magnetic flux guiding members 601 and 602 has a mainbody 600 which has a rectangular band shape in a plan view and collectsmagnetic flux, and two extensions 61 and 62 extending in the orthogonaldirection from the main body 600. Each of the extensions 61 and 62 areprovided so as to sandwich the magnetic sensors 71 and 72 in theupper-lower direction. In other words, the magnetic sensors 71 and 72are arranged between the set of magnetic flux guiding members 601 and602. In the magnetic flux guiding members 601 and 602, at least a partof the main body 600 faces the ring portions 35, 36 of the cylindricalyokes 31 and 32 housed in the housing 40, and the magnetic flux isinduced from the magnetic circuit formed in the yokes 31 and 32.Hereinafter, the rectangular band shape of the magnetic flux guidingmembers 601 and 602 are simply referred to as “straight lines”. Thedetailed configuration and operation of the magnetic flux guidingmembers 601 and 602 will be described later.

After the magnetic flux guiding embers 601 and 602, the magnetic sensors71 and 72, and the substrate 70 are housed in the box portion 51 of thecase 501, the box portion 51 of the case 501 is potted with molten resinfrom the opening end 52, and the storage parts are fixed therein.Further, as shown by the broken line in FIG. 6B, a lid 59 that closesthe opening end 52 may be used as a separate component. In that case,the upper magnetic flux guiding member 601 can be insert-moldedintegrally with the lid 59. In another embodiment, the opening end 52may be closed only by potting the molten resin without using the lid 59,or by using only the lid 59 without potting.

In this way, the case assembly 500 in which the magnetic flux guidingmembers 601, 602, the magnetic sensors 71, 72, and the substrate 70 arehoused in the case 501 is configured. The case assembly 500 can beindependently attached to the non-waterproof housing 401. Further, thecase assembly 500 can be attached to the waterproof housing 402 with thecap 801 attached to the insertion portion 53. When the case assembly 500is attached to a non-waterproof housing 401, the case assembly 500 aloneconstitutes a “magnetic detection module”. Although the part to whichthe cap 801 is attached is the case assembly 500 in the manufacturingprocess, it can also be expressed as “the cap 801 is attached to thecase 501” from the viewpoint of each part.

The cap 801 is formed of resin, and has a receiving hole 83 into whichthe insertion portion 53 of the case 501 is inserted, and is formed onan end surface of a disc-shaped cap body 811 on the case 501 side. Thereceiving hole 83 is opened in a rectangular shape corresponding to theshape of the insertion portion 53 of the case 501, and the depth of thereceiving hole 83 is deeper than the thickness of the cap body 811. Theprotrusion accommodating grooves 85 into which the protrusion portion 55is inserted are formed in the upper portions of both sides of thereceiving hole 83. As a result, when the insertion portion 53 isinserted into the receiving hole 83, it is prevented from being insertedin a 180° opposite direction.

On the end face of the cap body 811 opposite to the case 501, a sealingportion 84 that is connected to the end face and covers the bottom ofthe receiving hole 83 to form a bag is formed. The sealing portion 84protrudes in a rectangular parallelepiped shape from the cap body 811 onthe side opposite to the case 501, and an outer wall thereof is formedto be larger than an inner wall at the bottom of the receiving hole 83by a predetermined amount. In short, communication is blocked betweenthe outer wall of the sealing portion 84 and the inner wall of thereceiving hole 83 so that water does not leak.

On the outer circumference of the cap body 811, an outer flange portion863 on the opening surface side of the receiving hole 83 and an innerflange portion 88 on the protruding side of the sealing portion 84 areprovided in parallel, and an outer peripheral groove 82 is formedbetween the outer flange portion 863 and the inner flange portion 88. Onthe upper center of the outer flange portion 863, a protrusion portion871 protrudes in the outer diameter direction and is formed as a“misassembling prevention portion” and a “rotation regulation portion”.

An O-ring 89 as a “sealing member” is attached to the outer peripheralgroove 82. At this time, an inner peripheral surface of the O-ring 89comes into contact with the bottom wall of the outer peripheral groove82. The O-ring 89 may be mounted on the outer peripheral groove 82before assembling the cap 801 and the case 501, or may be mounted on theouter peripheral groove 82 after assembling the cap 801 and the case501.

FIG. 5B shows a torque detection device 101 in which the case assembly500 is independently mounted in the mounting hole 41 of thenon-waterproof housing 401. The insertion portion 53 of the case 501 isinserted into a substantially rectangular mounting hole 41. At thistime, the protrusion 54 on the lower side is inserted into the rotationrestricting groove 44, and the protrusion portions 55 on both uppersides are inserted into the rotation restricting groove 45. Therefore,when the case assembly 500 is assembled to the housing 401, it isprevented from being erroneously assembled into the mounting hole 41 inthe 180° opposite direction. Further, after being assembled, therotation of the case assembly 500 with respect to the housing 401 isrestricted.

FIG. 6B shows the torque detection device 101 in which the magneticdetection module 901 with the cap 801 attached to the case assembly 500is attached to the mounting hole 42 of the waterproof housing 402. Thesealing portion 84 of the cap 801 is inserted into the substantiallyrectangular case hole 421, the inner flange portion 88 is inserted intothe seal hole 422, and the outer flange portion 863 is inserted into thespigot hole 423. At this time, by inserting the protrusion portion 871into the rotation restricting groove 471, when the magnetic detectionmodule 901 is assembled to the housing 402, it is prevented from beingerroneously assembled to the mounting hole 42 in the 180° oppositedirection. Further, after being assembled, the rotation of the magneticdetection module 901 with respect to the housing 402 is restricted.

The outer peripheral surface of the O-ring 89 is pressed against theinner wall of the seal hole 422 while being attached to the mountinghole 42. Therefore, as indicated by a bidirectional arrow Cp, the O-ring89 is radially compressed and used for a shaft seal. Compared to faceseal, shaft seal is less susceptible to dimensional variations inseal-related parts and tilt during assembly, and has excellent sealingfunction.

Next, with reference to FIGS. 9A to 12 , a modified example of the firstembodiment in which the configurations of the “misassembling preventionportion” and the “rotation regulation portion” in the mounting of thecap 801 and the housing 402 are different will be described. FIGS. 9Aand 11A are schematic cross-sectional views showing a state in which thecap 801 is attached to the housing 402. The schematic cross-sectionalview shows a schematic cross-sectional view in which the cap 801 and thecase 501 are combined, and an accurate illustration of the internalstructure as shown in FIG. 6B is omitted. Further, a prismatic portioncovered with the bag portion 84 protruding from a tip surface of the capbody 811 is referred to as “sensor unit 840”. The magnetic sensors 71and 72 are housed in the sensor unit 840. Here, “being housed” includesa configuration “being molded”.

FIGS. 9B and 11B are radial cross-sectional views showing a“misassembling prevention portion” and a “rotation regulation portion”provided on the cap 801 or the housing 402 on the base end side of thecap 801. FIGS. 10 and 12 are perspective views of the mounting hole 42of the housing 402 corresponding to FIG. 3B.

In the first modification shown in FIGS. 9A to 10 , a protrusion portion871 similar to that in FIG. 4 is formed on the upper part of the capbody 811 and a pair of twin protrusion portions 872 are formed at thelower part of the cap body 811 so as to project substantially parallelto the outer diameter at predetermined intervals. On the end surface ofthe housing 402, a rotation regulation convex portion 472 interposedbetween the twin protrusion portions 872 is formed. On the other hand,the portion of the end face of the housing 402 facing the protrusionportion 871 is a flat end face without unevenness.

By assembling the cap 801 to the housing 402 at the rotation positionwhere the twin protrusion portions 872 interpose the rotation regulationconvex portion 472, the twin protrusion portion 872 functions as a“rotation regulation portion”. Further, when assembling the cap 801 tothe housing 402, if the position in the rotation direction iserroneously assembled by 180°, the protrusion portion 871 interfereswith the rotation regulation convex portion 472 of the housing 402, sothat the protrusion portion 871 functions as “misassembling preventionportion”. As described above, in the first modification, each of theprotrusion portion 871 and the twin protrusion portions 872 of the capbody 811 shares the functions of the “misassembling prevention portion”and the “rotation regulation portion” by utilizing the rotationregulation convex portion 472 of the housing 402.

In a second modification shown in FIGS. 11A to 12 , a protrusion portion874 projecting in the outer diameter direction is formed in a lowerportion of the cap body 811. An upper part of the cap body 811 is asimple cylindrical surface without unevenness. The housing 402 is formedwith a rotation restricting groove 474 in which the tip of theprotrusion portion 874 engages with the pedestal portion 46 below themounting hole 42. Further, an interference protrusion portion 473 isformed at the edge portion of the mounting hole 42 on the side oppositeto the rotation restricting groove 474.

By assembling the cap 801 to the housing 402 at the rotation positionwhere the tip of the protrusion portion 874 engages with the rotationrestricting groove 474, the protrusion portion 874 functions as a“rotation regulation portion”. Further, when assembling the cap 801 tothe housing 402, if the position in the rotation direction iserroneously assembled by 180°, the protrusion portion 871 interfereswith the interference protrusion portion 473 of the housing 402, so thatthe protrusion portion 874 functions as “misassembling preventionportion”. As described above, in the second modification, the protrusionportion 874 of the cap body 811 functions as an “misassemblingprevention portion” by utilizing the interference protrusion portion 473of the housing 402, and functions as a “rotation control portion” byutilizing the rotation restricting groove 474 of the housing 402.

Next, the configurations of the magnetic flux guiding members 601 and602 of the present embodiment will be described with reference to FIGS.13A to 14 . FIGS. 13A to 14 are three views of a plan view, a side view,and an axial sectional view, in which a magnetic flux transmissionaction showing the magnetic flux transmission action between the yokes31 and 32, the magnetic flux guiding members 601 and 602 and themagnetic sensors 71 and 72 is shown with the case assembly 500 attachedto the housing. The plan view means a view seen from the first axis 11side in the axial direction, and the side view means a view seen fromthe radial direction.

Strictly speaking, the “plan view” is a radial cross-sectional view inwhich the multipolar magnet 14 and the claws 33 and 34 of the yokes 31and 32 are cut at the upper part of the upper magnetic flux guidingmember 601, and it is referred to as a “plan view” form the viewpoint ofthe magnetic flux guiding member 601. Further, although the ring isactually visible only in the lower yoke 32 in the radial cross-sectionalview, the reference numerals are given as “31, 32” including the upperyoke 31 for convenience of explanation.

In the plan view of FIG. 13A, a “reference line X” extending in theleft-right direction through the central axis O is described. Thereference line X is defined as a virtual straight line connecting theintermediate positions of the two magnetic sensors 71 and 72 and thecentral axis O. In other words, the two magnetic sensors 71, 72 arearranged symmetrically with respect to the reference line X. In theembodiment of one magnetic sensor, the reference line X is defined as avirtual straight line connecting the magnetic sensor and the centralaxis O.

The side view of FIG. 13B is a view of the magnetic sensors 71 and 72viewed from the outside in the radial direction along the reference lineX. The alternate long and short dash line indicates an outer shape ofthe claws 33 and 34. In the side view of FIG. 13B, the torsion bar 13and the multipolar magnet 14 are not shown. The axial sectional view ofFIG. 14 is a cross-sectional view on a plane including the central axisO and the reference line X. In the axial sectional view, the torsion bar13 is not shown, and the multipolar magnet 14 shows only the outline.

In the present embodiment, in a plan view, the main bodies of themagnetic flux guiding members 601 and 602 are formed in a rectangularband shape symmetrical with respect to the reference line X, that is, ina straight line shape. The longitudinal sides of the magnetic fluxguiding members 601 and 602 are straight lines orthogonal to thereference line X.

The magnetic flux guiding members 601, 602 have the extensions 61 and 62extending radially outward from the main body 600, and the “branchportion of the main body 600 to the extensions 61 and 62” is referred toas a S portion. The “branch portion to the extensions 61 and 62”substantially means the vicinity of the magnetic sensors 71 and 72. The“S portion” is the same symbol as the S pole of the multipolar magnet14, but the distinction between them is obvious and there is no risk ofconfusion. Portions of each of the main bodies 600 of the magnetic fluxguiding members 601 and 602 corresponding to ends of the yokes 31 and 32in the circumferential direction across the reference line X within arange where the main bodies 600 face the yokes 31 and 32 are defined as“circumferential end portions 63 and 64 of the main body 600” andhatched with broken lines in the drawing. A distance ds from the Sportion to the central axis O is shorter than the distance de from thecircumferential end portions 63 and 64 to the central axis O.

In the side view and axial-direction sectional view, each of themagnetic flux guiding members 601 and 602 faces a surface of the ringportion of the corresponding one of the yokes 31 and 32 from inside ofthe yokes 31 and 32 in the axial direction with a constant gap. The areawhere each of the magnetic flux guiding members 601 and 602 faces thesurface of the ring portion of the corresponding one of the yokes 31 and32 (the area hereinafter referred to as the “facing area”) is relativelylarge at a corresponding intermediate portion 65 that is close to themagnetic sensors 71 and 72, and becomes smaller at locations closer tothe corresponding circumferential end portions 63 and 64. The Sportions, which are locations from which the extensions 61 and 62 arebranched, have larger facing areas than do the circumferential endportions 63 and 64, thus having greater magnetic permeance per unit areabetween each of the magnetic flux guiding members 601 and 602 and thecorresponding one of the yokes 31 and 32. Here, “per unit area” issignificant in that, when magnetic permeance is compared betweendifferent locations, the wording explicitly states that the areas of thelocations are the same. In the description of the embodiments providedbelow where the wording “per unit area” is omitted, it is to beunderstood that “magnetic permeance” means “magnetic permeance per unitarea.”

The magnetic sensor 71 is disposed between the extensions 61, and themagnetic sensor 72 is disposed between the extensions 62. The extensions61 are each bent to have a step in the axial direction so as to have aminimum gap therebetween in a location where the magnetic sensor 71 isplaced. The extensions 62 are each bent to have a step in the axialdirection so as to have a minimum gap therebetween in a location wherethe magnetic sensor 72 is placed.

Next, with reference to FIG. 15 , the reason why the signal becomeslarge due to the above mentioned configuration will be described. FIG.15 shows a correlation diagram between the distance from the referenceline X or the rotation angle and the magnetic permeance for the magneticpermeance between the magnetic flux guiding members 601, 602 and theyokes 31 and 32. The magnetic permeance P is represented by the formula(1) using a magnetic permeability p of the material, a facing area A,and a gap length L.P=μ(A/L)  (1)

Here, assuming that the magnetic flux guiding members 601 and 602 areformed of a single soft magnetic material, the larger the facing area Abetween the magnetic flux guiding members 601 and 602 and the yokes 31and 32, or a shorter gap length L, results in greater magnetic permeanceP. In the present embodiment, the gap between the magnetic flux guidingmembers 601 and 602 and the yokes 31 and 32 is constant, but the facingarea becomes smaller from the intermediate portion 65 toward thecircumferential end portions 63 and 64, so that the magnetic permeanceof the intermediate portion 65 is larger than the magnetic permeance ofthe circumferential end portions 63 and 64. In FIG. 15 , the correlationcharacteristic may be any characteristic such as a straight line likeP1, a simple curve without an inflection point like P2, an S-shapedcurve like P3, or a stepped polygonal line.

The magnetic sensors 71 and 72 are arranged in the extensions 61 and 62branched from the main body 600 near the intermediate portion 65, andthe branch portion of the magnetic flux guiding members 601 and 602 tothe extensions 61 and 62 in the main body 600 substantially means“vicinity of the magnetic sensors 71 and 72”. The magnetic flux guidingmembers 601, 602 are configured that the “magnetic permeance per unitarea between the magnetic flux guiding members 601, 602 and the yokes 31and 32” at the branch portion to the extensions 61 and 62 is larger thanthat at the circumferential end portions 63 and 64. As a result, thesignals of the magnetic sensors 71 and 72 can be increased.

Next, a method of manufacturing the magnetic detection module will bedescribed with reference to the flowchart of FIG. 16 . In thedescription of the flowchart, the symbol S represents a “step”. In astorage process of S10, the magnetic flux guiding members 601, 602, themagnetic sensors 71, 72, the substrate 70, and the like are housed inthe box portion 51 of the case 501. Then, for example, the molten resinis potted in the remaining space of the box portion 51, and the magneticsensors 71 and 72 are fixed. Further, the box portion 51 may be coveredwith a lid 59. In this way, the case assembly 500 is manufactured in thestorage process S10.

In a selection process of S20, according to the specifications of thehousing to be attached, it is selected whether to use the case assembly500 alone or to attach a cap 801 set for each housing specification tothe end of the case 501. In the first embodiment, it is determinedwhether the case assembly 500 is attached to the non-waterproof housing401 that does not require the sealing member or the waterproof housing402 that requires the sealing member.

In S25, the selection result is determined. When the case assembly 500is attached to the waterproof housing 402, it is determined as YES inS25, and the process proceeds to the attachment process of S30. When thecase assembly 500 is attached to the non-waterproof housing 401, it isdetermined as NO in S25, and the process ends. In this case, the caseassembly 500 is used alone without the cap 801 being attached.

In a mounting process of S30, the cap 801 is mounted and fixed to thecase 501. In the configuration of the first embodiment, the insertionportion 53 formed at the end of the case 501 is inserted into thereceiving hole 83 formed in the cap 801. After that, a joint portionbetween the insertion portion 53 of the case 501 and the receiving hole83 of the cap 801 is welded by laser welding or the like. Here, even ina configuration in which the sealing portion 84 that covers the bottomof the receiving hole 83 to form a bag as shown in FIGS. 4 to 8B is notprovided, the joint portion surrounding the magnetic sensors 71 and 72is welded all around. Therefore, water leakage from the bottom of thereceiving hole 83 can be prevented.

The cap 801 may be fixed with an adhesive in the mounting process. Whenthe molten resin is potted in the storage step, it is preferable thatthe potting is cured and the adhesive is cured at the same time. As aresult, the cycle time can be shortened.

As described above, the magnetic detection module 901 of the firstembodiment can change the mounting specifications to the housing 40depending on the presence or absence of the cap 801. Specifically, forthe waterproof housing 402, a magnetic detection module in which the cap801 provided with the sealing member 89 is attached to the case 501 issupplied. Further, for the non-waterproof housing 401, the case assembly501 without the cap 801 is independently supplied as a magneticdetection module. Therefore, for example, when the case 501 ismanufactured by resin molding, only one type of mold is required for thecase 501, and inventory management is simplified.

Second Embodiment

Next, with reference to FIGS. 17A to 18B, a magnetic detection module902 of the second embodiment provided with the magnetic shield memberwill be described. The magnetic shield member is made of a soft magneticmaterial such as iron or permalloy, and blocks magnetic noise from theoutside.

In the form shown in FIGS. 17A to 17C, a rectangular frame-shapedmagnetic shield member 37 is provided at the insertion portion 53 of thecase assembly 500 that is independently attached to the non-waterproofhousing 401. Specifically, after the molten resin is potted on the case501, the magnetic shield member 37 is covered so as to surround themagnetic sensors 71 and 72 from all sides. Therefore, the magnetic noisedirected to the magnetic sensors 71 and 72 is effectively blocked.

In the form shown in FIGS. 18A and 18B, a pair of arch-shaped magneticshield members 38 are provided on the cap 801 of the magnetic detectionmodule 902 attached to the waterproof housing 402. The pair of magneticshield members 38 are provided so as to surround the sealing portion 84from the upper-lower direction. As shown in FIG. 18B, the magneticshield member 38 is arranged so that a center line Ds in the depthdirection overlaps the magnetic sensors 71 and 72. Therefore, themagnetic noise directed to the magnetic sensors 71 and 72 is effectivelyblocked.

Third Embodiment

Next, a third embodiment will be described with reference to FIG. 19 . Atorque detection device 103 of the third embodiment includes a housing402 having a mounting hole 42 whose inner wall is cylindrical, and amagnetic detection module 903 mounted in the mounting hole 42. Althoughnot shown in FIG. 19 , a set of yokes 31 and 32 for transmittingmagnetic flux generated according to the magnitude of torque is providedinside the housing 402. The magnetic detection module 903 detects themagnetic flux transmitted from the yokes 31 and 32 with one or moremagnetic sensors 71 and 72.

Similar to the first embodiment, the magnetic detection module 903 ofthe third embodiment has a disc-shaped cap 803 attached to the tip ofthe case 501. An outer peripheral surface of the cap body 813 in the cap803 faces the inner wall of the mounting hole 42. However, in the cap801 of the first embodiment, the outer peripheral groove 82 is formedbetween the outer flange portion 863 and the inner flange portion 88. Onthe other hand, the cap 803 of the third embodiment is not provided withan inner flange portion, and a step portion 823 in the radial directionis formed on the outer periphery. In the example of FIG. 19 , the O-ring89 as a sealing member for the shaft seal is attached to the stepportion 823, but in other embodiments, the O-ring 89 may not beprovided. The step portion 823 is composed of a step between a largediameter portion 866 on the base end side of the cap body 813 and asmall diameter portion 865 on the tip end side thereof. The largediameter portion 866 and the small diameter portion 865 correspond tothe “large shaft portion” and the “small shaft portion”.

The mounting hole 42 has a case hole 424, a small diameter hole 425, alarge diameter hole 426, and a chamfered portion 427 in order from theback with respect to the end surface 428 side. The large diameter hole426 and the small diameter hole 425 correspond to the “large hole” andthe “small hole”. The large diameter portion 866 of the cap 803 isinserted into the large diameter hole 426, and the small diameterportion 865 is inserted into the small diameter hole 425. On the baseend side of the large diameter portion 866, a flange portion 868 thatabuts on an end surface 428 of the housing 402 is formed. Further, thesensor unit 840 projects from the tip surface of the cap body 813. Thetip of the sensor unit 840 is inserted between the ring portions 35, 36of the set of yokes 31, 32.

In the torque detection device 103 of the third embodiment, thedimensional relationship of the fitting gap between the large diameterportion 866 and the large diameter hole 426 or the small diameterportion 865 and the small diameter hole 425 and the gap between thesensor unit 840 and the ring portion of the yoke is adjustedappropriately. Since the configuration and the effect regarding thedimensional relationship are the same as the configuration and theeffect of the torque detection device 104 of the following fourthembodiment, they will be described together in the fourth embodiment.

Fourth Embodiment

Next, a fourth embodiment will be described with reference to FIG. 20 .A torque detection device 104 of the third embodiment includes thehousing 402 having the mounting hole 42 whose inner wall is cylindrical,and a magnetic detection module 904 mounted in the mounting hole 42.Similar to the third embodiment, a set of yokes 31 and 32 fortransmitting magnetic flux generated according to the magnitude oftorque is provided inside the housing 402. The magnetic detection module904 detects the magnetic flux transmitted from the yokes 31 and 32 withone or more magnetic sensors 71 and 72.

The magnetic detection module 904 is not intended to be selectivelymountable to a plurality of housings, and the mounting target is limitedto the housing 402 having a mounting hole 42 whose inner wall iscylindrical. The fourth embodiment aims to prevent interference betweenthe sensor unit 840 and the member on the housing 402 side when themagnetic detection module 904 is inserted into the housing 402.Therefore, the magnetic detection module 904 of the fourth embodiment isnot configured to have a cap of another member attached to the endportion of the case, but is configured by an integrated case 504. Thecase 504 is integrally formed of resin in a shape equivalent to thestate in which the cap 803 is attached to the case 501 in the thirdembodiment shown in FIG. 19 . That is, the one in which the case 501 andthe cap 803 are combined is the integrated case 504 of the fourthembodiment.

A portion corresponding to the cap body 813 of the cap 803 of the thirdembodiment is referred to as a “cylindrical portion 814” in the fourthembodiment. The cylindrical portion 814 corresponds to the “cylindricalportion” and faces the inner wall of the mounting hole 42. Further, thesensor unit 840 projects from the tip surface of the cylindrical portion814. In other words, the form in which the cylindrical portion 814 ofthe case 504 of the fourth embodiment is composed of the cap body 813 ofthe cap 803 of another member corresponds to the third embodiment. Inshort, the form in which the O-ring 89 is mounted in the thirdembodiment has both purposes, “selective mounting to a plurality ofhousings of waterproof and non-waterproof specifications” and“prevention of interference between the magnetic sensor and the housingside member”.

Therefore, the configuration of the cylindrical portion 814 and themounting hole 42 facing the cylindrical portion 814 of the fourthembodiment is substantially the same as the configuration of the capmain body 813 and the mounting hole 42 facing the outer peripheralsurface of the cap main body 813 of the third embodiment. The mountinghole 42 has a large-diameter hole 426 formed on the opening side and asmall diameter hole 425 formed at the back of the large-diameter hole426.

The cylindrical portion 814 has a flange portion 868 that abuts on theend surface 428 of the housing from the base end side toward the tip endside where the magnetic sensors 71 and 72 are arranged, a large diameterportion 866 that is inserted into the large diameter hole 426, and asmall diameter portion 865 that is inserted into the small diameter hole425. In the example of FIG. 20 , the O-ring 89 is attached to the outerperiphery of the small diameter portion 865 as a sealing member, but inother embodiments, the O-ring 89 may not be provided. The O-ring 89 isused for a shaft seal with respect to the inner wall of the smalldiameter hole 425.

Next, with reference to FIGS. 21 and 22 , the dimensional relationshipbetween the cap body 813 and the inner diameter of the mounting hole 42in the torque detection device 103 of the third embodiment, or thedimensional relationship between the outer diameter of the cylindricalportion 814 and the inner diameter of the mounting hole 42 in the torquedetection device 104 of the fourth embodiment. In the description ofthis part, terms such as “cylindrical portion 814” of the fourthembodiment are used as representatives. Regarding the third embodiment,for example, “cylindrical portion 814” may be read as “cap body 813”.

The cross-sectional view of the torque detection device 104 of FIGS. 21and 22 is schematic as in FIGS. 9A and 11A. The magnetic sensors 71 and72 are housed in the “sensor unit 840” which is a prismatic portionprotruding from the tip surface of the cylindrical portion 814. Here,“being housed” includes a configuration “being molded”. If the sensorunit 840 interferes with the member on the housing 402 side due tomisalignment or inclination when the magnetic detection module 904 isinserted into the mounting hole 42, the magnetic sensors 71 and 72 maybe damaged or their characteristics may change. Therefore, in the fourthembodiment, interference between the sensor unit 840 and the member onthe housing 402 side is prevented.

Specifically, the sensor unit 840 is inserted between the ring portions35, 36 of the pair of yokes 31, 32 facing each other. The magnetic fluxgenerated between the ring portions 35 and 36 passes through the sensorunit 840, so that the magnetic sensors 71 and 72 detect the magneticflux. The minimum distance between the sensor unit 840 and the ringportions 35 and 36 is defined as “sensor margin p”. As shown in FIGS. 21and 22 , when the position of the sensor unit 840 is not biased withrespect to the center of the ring portions 35 and 36, the sensor marginp is half the length obtained by subtracting the thickness of the sensorunit 840 from the distance between the ring portions 35 and 36.

FIGS. 21 and 22 show examples of two patterns having differentdimensional relationships regarding diameter. The dimensional symbolsfor each part are defined as follows. A “one-sided fitting gap”corresponds to one half of the fitting gap between the diameter of thehole and the diameter of the shaft. The letter “h” in the symbolrepresents the housing and the “s” represents the sensor.

φDh1: Inner diameter of large diameter hole 426 (=φds1+2×ε1)

φds1: Outer diameter of large diameter portion 866

ε1: One-sided fitting gap between the large diameter hole 426 and thelarge diameter portion 866

φDh2: Inner diameter of small diameter hole 425 (=φds2+2×ε2)

φds2: Outer diameter of small diameter portion 865

ε2: One-sided fitting gap between the small diameter hole 425 and thesmall diameter portion 865

In the embodiment shown in FIG. 21 , the one-sided fitting gap ε1between the large diameter hole 426 and the large diameter portion 866is set to, for example, a minute gap of less than 0.1 mm. That is, thefitting of the large diameter hole 426 and the large diameter portion866 has the spigot structure. Therefore, accuracy such as coaxiality andsquareness when the cylindrical portion 814 is inserted into themounting hole 42 is ensured. Further, the gap ε1 is set smaller than thesensor margin μ (ε1<μ). Preferably, the gap ε1 is set to be much smallerthan the sensor margin μ (ε1<<μ). The one-side fitting gap ε2 betweenthe small diameter hole 425 and the small diameter portion 865 may beequal to or larger than the gap ε1.

Regarding the axial dimensions of the cylindrical portion 814 and themounting hole 42 in this configuration, the distance from the insertionend of the large diameter hole 426 (that is, the boundary between thechamfered portion 427 and the large diameter hole 426) to the outer edgeof the ring portions 35 and 36 of the yokes 31 and 32 is defined as“housing side distance Lh1”. Further, the distance from the boundarybetween the large diameter portion 426 and the small diameter portion425 to the tip of the sensor unit 840 is defined as “sensor sidedistance Ls1”. The housing side distance Lh1 is set longer than thesensor side distance Ls1.

With such a dimensional setting, even if the shaft of the cylindricalportion 814 is tilted to the maximum with respect to the shaft of themounting hole 42 and the outer wall of the large diameter portion 866contacts the inner wall of the large diameter hole 426 on one side inthe circumferential direction, the fluctuation of the tip position ofthe sensor unit 840 is suppressed to be smaller than the sensor marginμ. Therefore, when the magnetic detection module is inserted, it ispossible to prevent the sensor unit 840 from interfering with the yokes31 and 32 which are housing side members.

In the embodiment shown in FIG. 22 , the one-sided fitting gap ε2between the small diameter hole 425 and the small diameter portion 865is set to, for example, a minute gap of less than 0.1 mm. That is, thefitting of the small diameter hole 425 and the small diameter portion865 has the spigot structure. Therefore, accuracy such as coaxiality andsquareness when the cylindrical portion 814 is inserted into themounting hole 42 is ensured. Further, the gap ε2 is set to be smallerthan the sensor margin μ (ε2<μ). Preferably, the gap ε2 is set to bemuch smaller than the sensor margin μ (ε2<<μ). The one-side fitting gapε1 between the large diameter hole 426 and the large diameter portion866 may be equal to or larger than the gap ε2.

Regarding the axial dimensions of the cylindrical portion 814 and themounting hole 42 in this configuration, the distance from the insertionend of the small diameter hole 425 (that is, the boundary between thelarge diameter hole 426 and the small diameter hole 425) to the outeredges of the ring portions 35 and 36 of the yokes 31 and 32 is definedas “housing side distance Lh2”. Further, the distance from the tipsurface of the cylindrical portion 814 to the tip of the sensor unit 840is defined as “sensor side distance Ls2”. The housing side distance Lh2is set longer than the sensor side distance Ls2.

With such a dimensional setting, even if the shaft of the cylindricalportion 814 is tilted to the maximum with respect to the shaft of themounting hole 42 and the outer wall of the small diameter portion 865contacts the inner wall of the small diameter hole 425 on one side inthe circumferential direction, the fluctuation of the tip position ofthe sensor unit 840 is suppressed to be smaller than the sensor marginμ. Therefore, when the magnetic detection module is inserted, it ispossible to prevent the sensor unit 840 from interfering with the yokes31 and 32 which are housing side members.

Next, with reference to FIGS. 23A to 25B, a configuration forrestricting rotation and preventing erroneous assembly of thecylindrical portion 814 with respect to the mounting hole 42 will bedescribed. For example, in the prior art of Patent Document 2 (U.S. Pat.No. 4,753,545), the magnetic ring is arranged in the outer diameterdirection of the magnetic yoke and faces the magnetic yoke in the radialdirection. In this configuration, it is effective to secure theconcentricity between the magnetic ring and the magnetic yoke bypositioning, but the position accuracy in the rotation direction doesnot significantly affect the performance. On the other hand, in thetorque detection device 104 of the fourth embodiment in which themagnetic sensors 71 and 72 are arranged between the ring portions 35 and36 of the set of yokes 31 and 32, positioning of the cylindrical portion814 with respect to the mounting hole 42 in the rotational direction isimportant. Further, it is important to prevent the magnetic detectionmodule 904 from being assembled in the wrong direction by, for example,180°.

FIGS. 23A, 24A, and 25A show the cross section of the cylindricalportion 814 in the cross section taken along the line A-A of FIGS. 21and 22 . FIGS. 23B, 24B, and 25B show the front view of the mountinghole of the housing according to the arrow in the B direction in FIGS.21 and 22 . The parts where the assembly cross sections of FIGS. 21 and22 are changed according to each of the shapes of FIGS. 23A to 25B arenot shown. Further, for example, when used for a column-mounted typethat does not require waterproofing, the O-ring 89 may be eliminated ineach figure.

In the example shown in FIGS. 23A and 23B, a protrusion portion 875protruding in the outer diameter direction is formed at one position inthe circumferential direction of the large diameter portion 866.Further, a rotation restricting groove 475 is formed at a correspondingportion of the mounting hole 42. This configuration example is similarto the configuration example of the protrusion portion 871 and therotation regulation portion 471 in FIGS. 3A, 3B, 4 and the like.However, in the example of FIG. 4 , the protrusion portion 871 is formedon the outer periphery of the outer flange portion 863 inserted into thespigot hole 423, whereas the example of FIG. 23A is different in thatthe protrusion portion 875 is formed on the outer periphery of the largediameter portion 866. As described above, there is no essentialdifference regardless of which part of the outer peripheral surface ofthe cylindrical portion 814 the protrusion is formed.

In this example, the rotation of the cylindrical portion 814 isrestricted by engaging the protrusion portion 875 with the rotationrestricting groove 475. Further, it is possible to assemble only in aposture in which the relative angle between the cylindrical portion 814and the mounting hole 42 is located at a regular angle, and theerroneous assembly is prevented in a posture located at a posture otherthan the predetermined relative angle. In this way, the protrusionportion 875 and the rotation restricting groove 475 function as both a“misassembling prevention portion” and a “rotation regulation portion”.

In the example shown in FIGS. 24A and 24B, a flat portion 876 is formedon one side of the large diameter portion 866 in the circumferentialdirection. Further, a rotation restricting recess 476 is formed at acorresponding portion of the mounting hole 42. The flat portion 876corresponds to a form in which the width of the protrusion portion 875is widened and the protrusion length with respect to the outer diameterof the large diameter portion 866 is shortened. In the example of FIG.24A, the protrusion length of the flat portion 876 with respect to theouter diameter of the large diameter portion 866 is set to besubstantially 0. Further, the flat portion 876 may be formed on theminus side (that is, the center side) with respect to the outer diameterof the large diameter portion 866, and the outer peripheral shape of thelarge diameter portion 866 may be a D shape in which a part in thecircumferential direction is connected by a straight line. In thisexample, when the flat portion 876 engages with the rotation restrictingrecess 476, the flat portion 876 and the rotation restricting recess 476function as both a “misassembling prevention portion” and a “rotationregulation portion”.

In the example shown in FIGS. 25A and 25B, a separation portion 877 isformed at a position separated in the outer diameter direction from thecircular large diameter portion 866. The separation portion 877 isconnected to a collar portion 868 via a connecting portion 878 indicatedby the alternate long and short dash line. Further, a rotationrestricting hole 477 is formed at a corresponding portion of themounting hole 42. For example, when the rotation control hole 477 isformed in the housing 402 by post-processing, the processing is easybecause the shape is simple. In this example, the separation portion 877is fitted into the rotation restricting hole 477, so that the separationportion 877 and the rotation restricting hole 477 function as both the“misassembling prevention portion” and the “rotation regulationportion”.

In each of the configurations of FIGS. 23A to 25B, the positions of theprotrusion portion 875, the flat portion 876, and the separation portion877 are not limited to the shown positions, and may be any position inthe circumferential direction. Further, a plurality of these portionsmay be arranged in the circumferential direction. However, whenfunctioning as a “misassembling prevention portion”, a plurality ofthese portions need to be arranged at rotationally asymmetricalpositions so that there are no plurality of rotationally symmetricpositions. Further, as in the modified example of the first embodimentshown in FIGS. 9A to 12 , a convex portion may be provided on thehousing 402 side.

Other Embodiments

(A) The cap 801 in the form shown in FIGS. 4 to 8B has a bag-shapedsealing portion 84 formed at the tip thereof. However, as the cap 801, acap 805 whose tip is not bag-shaped may be used as in the magneticdetection module 905 shown in FIG. 26 . Compared to the form in whichthe sealing portion 84 is formed at the tip, in this form, the distance(gap) between the yokes 31 and 32 and the facing portions of themagnetic flux guiding members 601, 602 is smaller by the thickness ofthe resin at the tip, so that the sensitivity can be improved. In thiscase, in order to prevent water from entering from the interface betweenthe cap 805 and the case 501, it is necessary that the contact portionshown by the portion (*) in FIG. 26B is sealed with laser welding or anadhesive.

(B) In the first and second embodiments, the O-ring 89 as a sealingmember is mounted in the outer peripheral groove 82 of the cap 801 andis used for the shaft seal between the O-ring 89 and the inner wall ofthe mounting hole 42 of the housing 402. As another sealing member, anO-ring, packing, gasket, or the like used for surface sealing may beprovided on the cap. Further, the sealing member is not limited to theone for waterproofing, and may be one for oil sealing or gas sealing.Further, the shape of the portion of the outer periphery of the cap body811 on which the O-ring 89 is mounted is not limited to the outerperipheral groove 82, and may be a stepped shape in the radial directionas in the third and fourth embodiments.

(C) In the first and second embodiments, attachment to two types ofhousings 401 and 402 being waterproof and non-waterproof, can beselected depending on whether or not the cap 801 is attached to the case501. In addition, for example, if there are O-ring specifications forshaft seals and packing specifications for surface seals amongwaterproof specifications, or if there are specifications with differentsizes of O-rings, a cup suitable for each specification may be selectedand attached to the case. Alternatively, the cap may be attached to thecase as an adapter for a plurality of non-waterproof housings havingdifferent shapes and sizes of mounting portions.

(D) The number of magnetic sensors included in the magnetic detectionmodule is not limited to two as exemplified in the above embodiment, andmay be one or three or more. Further, the magnetic detection module doesnot include the magnetic flux guiding members 601 and 602, and themagnetic flux generated in the housing 40 may be directly transmittedfrom the set of yokes 31 and 32 to the magnetic sensors 71 and 72. Inthe configuration including the magnetic flux guiding members 601 and602, the shape of the main body of the magnetic flux guiding member isnot limited to the linear shape, but may be an arc shape along the yokeor the like, and the extension may not be provided. Further, themagnetic flux guiding member may face the set of yokes 31 and 32 in theradial direction instead of the axial direction.

(E) The case 501 and the cap 801 are not limited to resin moldedproducts, and may be manufactured of other materials that do not affectmagnetic detection. Further, the method of attaching the cap 801 to thecase 501 is not limited to the method of inserting the insertion portion53 of the case 501 into the receiving hole 83 of the cap 801 and weldingor adhering the joint portion, and for example, the cap 801 may beattached to the case 501 by press fitting or the like.

(F) The shapes of the misassembling prevention portion and the rotationregulation portion to the housings 401 and 402 are not limited to theprotrusion portion, groove, and the like shown in the above embodiment.In addition, the positions and numbers of the misassembling preventionportion and the rotation regulation portion may be appropriately set.Further, the form is not limited to a form having both functions, andmay have only a misassembling prevention function or only a rotationregulation function. For example, the asymmetrical shape may form amisassembling prevention portion. In addition, if the purpose ofmisassembling prevention or rotation regulation is achieved by otherconfigurations, the misassembling prevention portion or rotationregulation portion may not be provided.

(G) The cylindrical portion 814 of the fourth embodiment is not limitedto a cylindrical shape, and may be formed as a “cylindrical portion”including an elliptical cylinder shape, a long cylinder shape, apolygonal cylinder shape, and the like. The same applies to the cap body813 of the third embodiment. If it is an elliptical cylinder portion ora long cylinder portion, a sealing function by an O-ring is alsoensured. In addition, if it is an elliptical cylinder portion, it can beexpressed using “diameter”, but if it is difficult to apply the conceptof “diameter” to a non-cylindrical cylinder portion, the large diameterpart may be generalized as a “large shaft part” and the small diameterpart may be generalized as a “small shaft part”.

Further, the large diameter hole and the small diameter hole of themounting holes facing each other may be generalized as “large holes” and“small holes”. Further, the direction orthogonal to the axial directionof the cylindrical portion and from the center to the peripheral edge isdefined as a pseudo “diameter direction”, and the gap between the shaftportion and the hole on one side in the radial direction in the spigotstructure is referred to as “one-sided fitting gap”.

(H) The detection device of the present disclosure or the detectiondevice to which the magnetic detection module of the present disclosureis applied is not limited to the torque detection device of the electricpower steering device, and the detection device may detect the magneticflux generated according to the magnitude of the physical quantity to bedetected. The generated magnetic flux is transmitted by a set of yokesprovided inside the housing and detected by the magnetic sensor of themagnetic detection module. For example, it can be used as a rotationdetection device, a position detection device, or the like that detectsmagnetic flux generated in response to rotation or linear movement of amovable body.

The present disclosure should not be limited to the embodiment describedabove. Various other embodiments may be implemented without departingfrom the scope of the present disclosure.

The present disclosure has been made in accordance with the embodiments.However, the present disclosure is not limited to such embodiments andconfigurations. The present disclosure also encompasses variousmodifications and variations within the scope of equivalents.Furthermore, various combination and formation, and other combinationand formation including one, more than one or less than one element maybe made in the present disclosure.

What is claimed is:
 1. A detection device, comprising: a housingincluding a mounting hole provided inside with a set of yokes thattransmit the magnetic flux generated according to a magnitude of aphysical quantity to be detected; and a magnetic detection modulemounted in the mounting hole in the housing and configured to detect themagnetic flux transmitted from the yoke by one or more magnetic sensorshoused in a case, wherein the set of yokes has ring portions that faceeach other and form a magnetic circuit, the magnetic detection moduleincludes a cylindrical portion which is inserted into the mounting holeand faces an inner wall of the mounting hole, and a sensor unit in whichthe magnetic sensor is housed and protrudes from a tip end surface ofthe cylindrical portion and is inserted between the ring portions of theset of the yokes, the cylindrical portion and the housing includemisassembling prevention portions, when assembling the magneticdetection module to the housing, it is possible to assemble only in aposture located at a predetermined relative angle, and to preventerroneous assembly in a posture other than the predetermined relativeangle, in a direction orthogonal to an axial direction of the mountinghole and the cylinder portion, when a minimum distance between thesensor unit and the ring portion is defined as a sensor margin, anone-sided fitting gap between the mounting hole and the cylindricalportion is set to be smaller than the sensor margin.
 2. The detectiondevice according to claim 1, wherein the misassembling preventionportion also functions as a rotation regulation portion that regulatesrotation of the housing after the magnetic detection module is assembledto the housing.
 3. The detection device according to claim 1, whereinthe cylindrical portion is integrally formed with the case.
 4. Thedetection device according to claim 1, wherein the cylindrical portionis composed of a plate-shaped cap body of a cap attached to an endportion of the case.
 5. The detection device according to claim 1,wherein an O-ring as a sealing member used for shaft sealing is mountedon the outer periphery of the small shaft portion of the cylindricalportion with the inner wall of the mounting hole of the housing.
 6. Thedetection device according to claim 1, further comprising: a torsion barthat twists and displaces according to torque and is provided in thehousing, and a multipolar magnet that is fixed to one end side of thetorsion bar and is provided in the housing, wherein the set of yokes isfixed to the other end side of the torsion bar, forms a magnetic circuitin the magnetic field of the multipole magnet, and has the ring portionoutside the diameter of the multipole magnet, and the detection devicefunctions as a torque detection device that detects the magnetic fluxtransmitted from the yoke by the magnetic sensor and detects the torqueapplied to the torsion bar.